Oil-gas burner



June 21, 1960 F. A. LoEBEl. ETAI- 2,941,585

OIL-GAS BURNER Filed July 29, 1957 2 Sheets-Sheet 1 i fray 27]. 17u 5e/27 and, i' WW' fianza/47.5

Juli 2l, 1960 F A, LOEBEL -.TAL

OIL-GAS BURNER 2 Sheets-Sheet 2 Filed July 29, 1957 United States PatentOIL-GAS BURNER Frederick A. Loebel and Elroy M. Rulseh, Milwaukee,

Wis., assignors to Cleaver-Brooks Company, a corporation of WisconsinFiled July 29, 1957, Ser. No. 674,874

4 Claims. (Cl. 158-11) This invention relates to combustion apparatusadapted for burning either liquid or gaseous fuel, and has for a generalobject the provision of a new and improved apparatus of this type.

In combination oil and gas burning apparatus, a nozzle is providedadjacent the combustion zone for discharging oil in an atomized state tobe burned in the combustion chamber, and additional means is providedfor use alternatively to supply gaseous fuel .for combustion in the samecombustion chamber. Normally, the oil nozzle is positioned closelyadjacent the combustion zone in order to properly discharge the oil yforburning, and while the positioning of the nozzle in this manner isnecessary and advantageously contributes to the provision of acombination oil and gas burning apparatus, it also givesrise to certainproblems. i More speciiically, one of the problems encountered is thatexcessive heat on the oil nozzle while burning gas may be suiiicient tovaporize and coke any oil droplets left in the narrow nozzle passages,partially or totally blocking the passages. Thus, when burner operationis changed from gas firing to oil firing, oil atomization willbeadversely afected because of the coke in the nozzle passages, andcombustion will be poor. Further, it is possible, even if the oil nozzleis properly purged of oil, leaving only a thin film, that the heat onthe oil iilm within the nozzle may bake the film so that it is dicult totake the nozzle apart for cleaning.

The problem is best solved by removing the nozzle from the hot zone, butit is essential that the changeover from gas tiring to oil firing andvice versa, be as simple as possible with a minimum of manipulationsrequired. j Accordingly, with the above and other considerations inmind, it is a more specific object of the invention to provide a new andimproved combination oil and gas burner apparatus including meansmounting the oil burner nozzle for movement from an advanced oil firingposition closely adjacent to the combustion zone toV a retracted,protected position to reduce the heat on the nozzle during 'gas tiring.

`Another `object is to provide a new and improved comA bination oil andgas burner apparat-us of the type described in the preceding paragraphincluding control means to prevent oil iiring when the oil nozzle is inthe Aretracted gas firing position. l AOther objects and advantages willbecome readily apparent from the following detailed description taken in,connection with the accompanying drawings, in which: v Fig. 1 is afragmentary vertical sectional view taken along the longitudinal axis ofa boiler structure embodying the principles of the present invention;

Fig. 2 is an enlarged fragmentary left end elevational view of theboiler structure illustrated in Fig. l;

e l CC tended to limit the invention to the embodiment illustrated. Thescope of the invention will be pointed out in the appended claims.

Referring now to the drawings, as illustrated, the invention Visembodied in a horizontal iire tube boiler which includes a horizontallydisposed tubular boiler shell which may be supported by any suitablemeans. Near the end of the boiler shell shown in Fig. 1, a tube sheet 11extends across the shell and is suitably secured thereto as yby weldingillustrated at 12, and together with similar means provided at the endof the boiler shell not illustrated provides a means for supporting alire tube 13. The re tube 13 and additional smaller tubes such as thatillustrated at 14, with suitable additional structure, form multiplepasses for combustion gases, through the boiler to an exhaust stack allas is conventional in boiler equipment of the type illustrated.

The iire tube 13 comprises a horizontally disposed, generallycylindrical tube of suitable metal material having an end tted in anopening in the tube sheet 11 and welded to the sheet as illustrated at15. The tire tube is lined with suitable refractory material asillustrated at 17 and 118, and insulating material as illustrated at 19,and the re tube, together with the refractory materials form acombustion chamber in which combustion `gclurs during gas tired and oilfired operation of the o er. i

An annular body of insulating material 20 is positioned at the end ofthe fire tube as illustrated, and is supported by an annular casing 21having a channel shaped across section and including an outwardlyextending mounting iiange 22. The ange 22 is iitted on a series of bolts23 which are welded to van annular ring 24 in turn welded inside thetire tube. The flange 22 abuts a sealing ring 25 and is secured inposition by nuts 26.

At the front end of the boiler, the shell 10 is closed -by an innerfront boiler door 30 in the form of a circul lar plate which may besecured to a shell flange 31 by any suitable means such as bolts andnuts, or by a hinge mechanism, or bywboth means. In addition to theinner door 30, the front of the boiler shell is closed by an outerdish-shaped boiler door 33 of generally cylindrical conguration andincluding an outwardly turned flange 34 which abuts against the innerdoor 30' and which may be secured to the boiler shell in a suitablemanner. The

` ldish-shaped outer door and the inner door 30 define an Fig.- 3 is anenlarged fragmentary sectional view simi i air plenum chamber into whichcombustion air is drawn from atmosphereand from which the combustion airflows to the combustion chamber to support burning during gas `iiringand oil tiring of the boiler.

A cylindrical `burner tube 36 is aligned with an openL ing 37 in theinner door 30 and with an opening 38 in the refractory 18. The burnertube deiines a chamber in which the oil nozzle 67 is mounted, and alsoforms an air duct through which combustion air Hows from the plenumchamber to the combustion chamber. The burner tube is supported by anoutwardly extending annular ange 39 welded to the tube and supported onthe inner door 30 by machine screws 40. A sealing ring 4l is positionedbetween the flange 39 and the door 30 to prevent leakage of gases.

Combustion air is drawn into the plenum chamber through a `suitableopening 44 provided in the outer door 33 by means of a blower whichconsists of a fan wheel 45 mounted on the drive shaft of a fan motor 46.The motor 46 may be supported in any suitable manner, but

preferably is conveniently mounted on the door 33. Air drawn into theplenum chamber by the fan passes to the burner-lube 36 througha vaneddittus-er or bafe 48 including a plurality of circumferntially spacedvaines 49 supported at opposite ends respectively by an outer annulaivplate f50 and an inner annular plate 51; The 'outer plate 50 is securedto Vthe outer door 33, with an intervening sealing member 52, by machine'screws' 53, andthe inner plate 51 is mounted on bolts v54 Welded to theburner tube -tlange 39. Nuts 55 secure the plate S1 in place, and asealing ring -56 is positioned between the rings 51 and 39.

The end of the burner tube 36 -adjacent the combustionfchamber Tisprovided with an air diffuser including 'a cylindrical side wall 58Whichis iitted in the burner tube and an end Wall 59 which extendsacross the duct provided by the cylindrical -Wall 58 and the burner tube36. The end wall 59 is provided with a central opening 60 and aplurality of circumferentially spaced, radially 'extending openings (notvisible) Wit-h adjacent baffles or louvers 61 'which function to directair passing through the idiiluser in a swirling pattern into the com'-bustion chamber to vprovide the proper air ow pattern and a uniformdistribution .of combustion air in the combustion zone. v

K Gaseous tuel is supplied to the combustion chamber 'for gas tiring ofthe burner through a gas conduit 63 which is positioned in outer spacedconcentric relationship 'to the burner tube .36. The gas conduit isWelded at one end to the kburner tube fla-nge 39', 4and is welded at theother tend to the channel vshaped casing 21. Theconduit 63, iwi-th theburner tube 36 and the casing 21, for-ms am annular .passage throughwhich gas -ows from a supply z-pipe 64 4to the .combustion chamber. AttheY end of the gas passage yadjacent the Vcombustion chamber, la ring65 is secured insidethe casing 21 as by welding, and fo-nn's Aarestriction in the gas Apassage which creates a slight pressure .drop.suieient to cause an even distribution .of :the gas iowing from theannular gas passage to the combustion chamber. The gas supply pipe 64leads from the conduit 63 through the .boiler .shell 10 for connectionwith a source .of gaseous fuel, and is provided with r.a suitable owcontrolling valve 66 .of a conventional construction lwhich 4iselectrically controlled to open and :close fthe [gas conduit, preferablyib'y `'a1-notorized operator.

`=Fuel oil is supplied to the combustion chamber for oil tiring ofthefburner by means Vincluding a -nozzle `67 which utilizes fuel foilsupplied by an `oil supply lpipe A68 and air under pressure Aforatoinizing the oil supplied by ian :air supply pipe 469 positioned'inouter spaced concentric relationship to the oil pipe 68.

- ,l The air supply pipe 69 is threaded into nozzle body 70 and extendsoutwardly 'from the nozzle t'o a :tting P71 which in turn has aconnection with a ilexible conduit 72 `adapted yfor connection with asource iof atomizing under pressure. lf desired, an vair pressure gauge7 3 maybe connected with thelitting 71.

At the `discharge end, Athe oil supply pipe 68 opens into nozzle tip 775vand is supported therein. At the other end, the oil pipe is connectedto a litting 76 in vturn connected to a supply conduit including aexible portion 77 and a rigid portion 78. The rigid conduit portion 78is adapted for connection with a suitable source of fuel oil, and visprovided with a flow controlling valve :80 of a conventional type whichis electrically controlled to `open and close the oil conduit -tocontrol the -ow -of jfuel `oil to the nozzle, preferably by a solenoidmeans.

The oil nozzle 67 and the air vand oil supply pipes 68 and-69 aresupported :in Van elongated tubular support 82 Twhich slidably Yreceivesthe inozzle 4body 70 and a collar 83on the ai'r pipe :.69 so that the-nozzle is mounted for movement from an advanced oil burning positionillustrated :in :full "-lines in Fig. `l to a retracted position for gastiring illustrated in broken lines in Fig. 1.

The tubular support 82 is mounted at the end adjacent port, and spacedradial legs 86 extending outwardly from the hub and having outer endssecured to the cylindrical ywall 5S of the ditluser. At the oppositeend, the tubular support is litted in a collar 87 provided on a closureplate 88 which is mounted on bolts 89 extending from the diuser plate50.Y

The oil nozzle may be locked in either the advanced oil tiring positionor the retracted position for gas firing by means including a pivotedlatch member 91 supported on a plate '92 having an integral collar 93secured on the atomizing air pipe .69. The pivoted latch member isthereby mounted for movement with the nozzle and the air and oil pipesduring advance or retraction of the latter, and is positioned tocooperate with a locking pin 95 suitably secured .to the closure plate88 and provided with a pair of spaced notches, such as that illustrated'at 96, one -for engagement by the hooklike Vend portion 91a of the latchmember when the nozzle is in the Iadvanced oil tiring position land onefor engagement by the latch member when the nozzle yis in the retractedposition. f

In order to Vprevent the initiation of oil tired burner operation whenthe oil `nozzle is in the retractedY g'as ring position, an`interlocking control switch 98 lis secured to the outside of Atheclosure plate 88, `and is Cp'r'ovided With a switch actuating plungerV-99 engag'eahle by the 4plate "92 on the air pipe when the -nozzleisinthe advanced oil ring position to close the switch to permit oil red`burner operation. When the Vnozzle is in the -retracted position forgas firing, the plate 92 frees the plunger 99 and the switch is lopenedto prevent oil fired burner operation, as will be explained in moredetail prmently in describing the electric circuit.

Gas tired Iand oil red operation of the burner apparatus `described lmaybe initiated by a conventional electrically controlled ignition system,generally designated 100 in the wiring diagram of Fig. 4 and, as seenin Fig. 1, including -a gas tired pilot burner 101 and Aa suitableelectric igniter 102. The gas burner 101 is in the form of an elongatedconduit opening at one `end adjacent the combustion chamber andconnected at the opposite end, exte'riorly of the mounting plate 88, to:a suitable pilot gas supply line 103. The electric igniter 102 isencased for =a portion of its length in suitable 1insulating means 104and extends exterio'rly v.of the mou-nting plate 88 for connection withsuitable wiring 105. The gas conduit 103 may be `connected with a supplyof gaseous fuel and, as is conventional, mayinclude a solenoid operatedpilot valve (not shown) forming a .part of the ignition system. Thewiring 105 may be connected with a suitable source `ofelectricpowerwhich conventionally includes `an ignition transformer (n'o'tshown) vforming -a part Vof the ignitionsystem. v

In operation, the oil nozzle 67 is positioned in the advanced full lineposition of Fig. l for oil red operation of the boiler, closely adjacentthe `combustion chambenin order that the nozzle will properly dischargethe atomized oil and air mixture into the combustion chamber to insureproper burning of theoil. When the boiler is operated on gaseous fuelsupplied through the conduit 63, the heat of the combustion may vbe sufiicient to cause coking or baking of the oil inthe passages of thenozzle 67 if the nozzle is left in the 'advanced oil firing position.Accordingly, the constructiondescribed permits retraction of the 'nozzlein a direction away'from the combustion chamber `to the broken linepositionof Fig. 1 wherein 'the heat on the nozzle lis suiciently1reduced to preventthe undesirable coking and baking re- Iferred to.Tests have been made, using thermocouple's to ascertain the heat on Vthenozzle,wh^ich clearlysildicate the temperature reductions atthe lnozzlefat various retracted positions. The tabulationgiven lbelovtfisTemperature at the nozzle tip in degrees Fahrenheit u Retractlon oi oilnozzle from oil burning position,

inches From the tabulation above it will be seen that retraction of thenozzle at least 5 inches from the oil burning position places the nozzlein a relatively cool temperature zone of vabout 215 F., about 115 coolerthan in the oil ring position, wherein coking and baking of the oil inthe nozzle passages cannot occur. Other tests conducted on larger andsmaller boilers show that in these also a 5 inch retraction of thenozzle is suilicient to prevent undesirable coking.

In addition to providing for retraction of the nozzle from the advancedoil tiring position to the withdrawn gas tiring position, the mountingmeans described above also permits removal of the nozzle and the supplypipes 68 and 69 completely from the tubular support 82 so that thenozzle is accessible exteriorly to permit maintenance and cleaning. Ifdesired, the outer door 33 may beprovided with a conveniently locatedbracket on which to hang the nozzle structure outside the plenum chamberwithout the need for disconnecting the flexible air supply conduit 72 orthe flexible oil supply conduit 77 while cleaning. y

As seen lin the electric circuit diagram of Fig. 4, a

gas-oil selector switch is provided to selectively obtain either gastired or oil iired operation of the boiler, The selector switch includestwo movable contacts 111 and 112l mechanically connected for `jointoperation under manual control. The movable contact 111 is adapted for,closure with la stationary contact 113 in the position illustrated inFig. 4 or to contact a stationary contact 114, whilethe movable contact112 cooperates with a stationary contact 115 when positioned asillustrated or with a stationary contact 116. As illustrated, theelectric circuit includes, in addition to the elements already referredto, a switch means 117 which is representative of one or moreautomatically operable limit control switches responsive to upper orlower limits of operating conditions to either open or close thecircuits automatically. Typical of such controls are water level,pressure, and temperature controls. Also, the circuit includes a switchmeans 118 which is representative of one or more manually operablecontrol switches for controlling burner operation at the will of anoperator, such as a manually operable burner switch for initiatingboiler operation.

In operation, in'order to obtain gas iired boiler operation with thelimit control switch 117 and the operating control switch 118 closed,the gas-oil selector switch is moved from the position illustrated inFig. 4 to a position in which the movable contact 111 engages thestationary contact 114 and the movable contact 112 engages thestationary contact 116. With the selector switch thus positioned, acircuit is completed from a suitable source of electric power through awire 120, the control switches 117 and 118, the movable contact 111, thestationary contact 114, -a wire 121, the movable contact 112, thestationary contact 116, -a wire 122, the electric gas valve 66, and awire 123 back to the source of power to energize the operating meanslfor the gas valve to open the valve, admitting gaseous fuel tocombustion chamber. At the same time, a circuit is completed from themovable contact 111, through stationary contact 114, a wire 124, a wire125, and the ignition 100 to energize the ignition system.Simultaneously, a circuit is completed from the wire 124 through a wire126 and the motor 46 to energize this motor thereby driving the fan 45to supply combustion air to the combustion chamber. The` ignition systemfunctions to admit gaseous fuel to the pilot burner and to ignite suchfuel, and the pilot burner in turn ignites the main supply of gaseousfuel. lIt will be seen lthat in obtaining gas red burner operation inthis fashion, the interlocking control switch -98 which is responsive tothe position of the oil nozzle is by-passed in energizing the gas valve,the ignition system and the blower motor, so that the condition of theinterlocking control switch is of no consequence to this operation.

In order to obtain oil tired operation of the boiler, the gas-oilselector siwtch is positioned as illustrated in Fig. 4, completing acircuit through the movable contact 111 the stationary contact 113, awire 127, the control switch 98, the wire 126 and motor 46 to energizethe motor, driving the fan to supply combustion air to the combustionchamber. At the same time, a circuit is completed through the wire 127,and the Wire 125 to energize the ignition system 100. Also, a circuit iscompleted through the wire `125, the wire 124, the wire 121, the movablecontact 112, the stationary contact 115, and a wire 128 to energize theelectric oil valve 80, opening the oil supply conduit 77 to permit theflow of fuel oil to the burner nozzle. Thus, it will be seen that Ioiltired burner operation requires closure of the control switch 98, andthereby requires that the nozzle be positioned in the advanced oilburning position in order to obtain energization of the motor 46, theignition system and the oil valve 80. Accordingly, oil fired burneroperation cannot be initiated if the oil nozzle 67 is in the retractedgas ring position.` This serves to prevent an attempted oil red burneroperation unless the oil nozzle is properly positioned for suchoperation.

It should be understood that the boiler operating control circuitillustrated :in fFig. 4 is a simpliiied circuit for purposes of clarityin describing the interlocking control switch 98, and in actual practicethe circuit will include additional controls not illustrated such as thelimit controls represented at 117, the operating controls represented at118, starters or the like for the motor 46 and program controls in theignition system which have not been illustrated in detail.

We claim:

1. In a burner apparatus for alternatively burning liquid or gaseousfuel, means forming a combustion chamber open at one end for admittingfuel and air to support combustion, a burner nozzle positioned centrallyin the open end of the combustion chamber for discharging liquid fuel inan atomized state into the combustion chamber, an air conduit disposedconcentrically around the burner nozzle for discharging combustion airinto the open end of the combustion chamber, a gas conduit disposedconcentrically around the air conduit for discharging gaseous fuel intothe open end of the combustion chamber, means mounting the burner nozzlefor movement between a rst, advanced position adjacent the open end ofthe combustion chamber for burning liquid and a second retractedposition away from the open end of the combustion chamber during gastiring, a fan for delivem'ng combustion air to the air conduit for gastiring and liquid firing, an electric motor for driving the fan, anelectrically controlled liquid valve controlling the flow of liquid fuelto the burner nozzle, an electrically controlled gas valve controllingthe ow of gaseous fuel to the gas conduit, electrically controlledignition means for initiating gas firing and liquid firing, circuitmeans including vsaid motor,l said valves, said ignition means and aselector switch selectively Vpositionable alternatively energizing saidliquid valve, said motor and .said ignition means for liquid iin-ing orsaid gas valve, Vsaid motor and said ignition means for gas lining, .andswitch means in said `circuit means responsive to the position oftheburner nozzle for preventing energization of the liquid valve, the motorandthe ignition means when the selector .switch is positioned lforliquid firing and :the burner nozzle is in the retracted gas ringposition, Y

2. VInra burner apparatus for `burning either gas or oil, means forminga combustion chamber, a conduit positioned to .discharge gaseous fuelinto the combustion chamber for gas firing of the burner, an oil burnernozzle positioned adjacent the combustion chamber for Idischargingatomized fuel oil into the chamber for oil iii-ing of the burner, meansmounting the oil nozzle for movement from an advanced position adjacentthe Vcombustion chamber for oil Afiring to a retracted position spacedfrom the combustion chamber to reduce the heat on -the nozzle during gasfiring, an electrically energizable gas valve vcontrolling the lflow ofgaseous fuel tothe gas conduit, an electrically energizable oil valvecontrolling the flow of oil to the nozzle, electrically energizableignition means Yfor initiating gas firing and oil firing, an electriccircuit including said valves and said ignition means, switch means insaid circuit selectively positionable for alternatively energizingeither said gas valve and said ignition means for gas firing or said oilvalve and said ignition means for oil tiring, and 'a switch in saidcircuit responsive to the position of the burner nozzle for preventingenergization of the oil valve and .ignition means when the selectivelypositionable switch means is positioned for oil firing and the burnernozzle is in the retracted `gas ring position.

3. In a burner apparatus for burning `either gas or oil, means forming acombustion chamber, a conduit positioned to discharge gaseous fuel -intothe combustion chamber for gas firing of the burner, lan oil burnernozzle positioned adjacent the combustion chamber Vfor discharg- -ingatomized fuel oil into the chamber for oil firing of the lburner, meansmounting the oil nozzle 4for movement lfrom an advanced positionadjacent the combustion chamber for oil iiring to a retracted positionspaced from the combustion chamber to reduce the heat on the nozzleduring 'gas tiring, a fan for delivering combustion air -to thecombustion chamber for gas ring and oil tiring, an electric motor fordriving the fan, an electrically energizable gas lvalve controlling theflow of gaseous .fuel tothe gas conduit, an electrically energizable oilvalve controlling the ow .of .oil to the nozzle, an electric circuitincluding said motor and said valves, switch means in said circuit se.-lectively positionable for alternatively energizing said gas valve andsaid motor for gas firing or for energizing said oil valve and saidVmotor for oil iiring, and a `switch in said circuit responsive to theposition of the burner nozzle for preventing energization of the oilvalve and the motor when said selectively positionable switch means ispositioned for oil Vfiring and the burner nzfZle is Qin tht/.1o -tractedgas ring position. Y Y' Y 4. In a burner apparatus for burning eitherOil or gas, means forming a combustion chamber, a conduit posi; tionedto discharge Vgaseous fuel into the .combustion chamber for gas tiring.of the burner, an Aoil .burner nozzle positioned in an opening to thecombustion chamber for discharging atomized oil linto the chamber foroil tiring of the burner, a fuel oil supply ,conduit having one endconnected to the o il nozzle for supplyllgl thereto, means slidablysupporting the oil nozzle and toil conduit for retraction from anadvanced position .wherein the nozzle is immediately adjacent ,thecombustion for oil ring to a second position wherein the nozzle 4`iswithdrawn and spaced from the combustion chamber dub ing gas firing toreduce vthe heat on thenozzle ,andthereby reduce coking of oil in thenozzle, and means for Ylocking the oil nozzle and `oil conduit in eitherposition, A cornprising, a latch `member support mounted for Amovementwith the .oil conduit, a pivoted latch member :on the latch membersupport, and a'latch .pin positioned alongside the path of the pivotedlatch member lwhen moved with the oil conduit, and having latchingnotches Atherein at spaced positions for engagement by the latch-memberrespectively when the nozzle and conduit are .in :the advanced andretracted positions.

l References .Cited in the file of this patent UNITED STATES PATENTS

